In a conventional art, in order to create a high-precision road map, precise position information related to a road marking, a guardrail, and the like is necessary. For this purpose, a method of performing analysis in which a two-dimensional image obtained by an in-vehicle monocular camera is used, and analysis is performed based on a luminance of the two-dimensional image, is known, for example. An example of such a technique is disclosed in Japanese Patent Application Laid-Open No. 1-242916.
Japanese Patent Application Laid-Open No. 6-266828 discloses a technique in which three-dimensional position data is calculated from a stereo image obtained by a stereo camera to detect a sidewall such as a guardrail.